I am sitting here looking down on an eagle, wafting imperiously and improbably slowly across a sublimely vast - in fact, rather scary - green-blue-grey Provencal gorge.

This is an unusual and thought-provoking place for an advanced species of urban man to find himself. I am a city person. The nocturnal thwump thwump thwumps of police helicopters are my nightingales, the early flights on final descent into City Airport my dawn chorus. I find the noise of traffic a comfort, the clatter of garbage trucks over speed bumps a cheering confirmation of the life force; litter, a sign of prosperity. Since we live on a busy stretch in central London, these tastes are a survival characteristic. One day recently, surprise overnight excavations closed the road and it became strangely silent, throwing us into existential panic when we woke.

And I enjoy being busy in the urban style, even occasionally foolishly over-stretched. Columns in newsapapers and magazines, two or three other sorts of articles on the go, a book to start or to finish, deadlines, crises, pitches, clients wanting reports or proposals. Radio stations wanting soundbites. Three cars and only two parking permits. Probably 30 serious emails every day, each demanding thoughtful attention. And I like running, playing tennis, going out in the evening, cooking and talking at very great length to my wife, children and friends.

I love all of this clamour, can't get enough, but this summer I decided to escape, to test myself with real isolation. EB White, the great New Yorker journalist, said: 'On any person who desires such prizes, New York will bestow the gift of loneliness and the gift of privacy.' I decided not to go to New York, but up an Alp.

Of course, we escape often. Mostly to the south of France, probably two or three times a year for the past quarter century. Usually to Nice, or to that part of Provence most familiar in the travel supplements. Nice is a marvellous city; and Peter Mayle's version of Provence is pleasant enough: at Isle sur la Sorgue, the antiques centre just east of Avignon, it is not la France Profonde, but it is somewhere you can reliably find both stacks of English Sunday papers in the bureau de presse and double-parked Range Rovers right outside collecting them.

A slick interiors magazine called Cote Sud has done even more to stylise this version of the south than Mayle: anywhere you find a shop selling galvanised jugs, scented candles, artfully distressed armoires, lavender bags and antique lace tablecloths betrays it. And you find them almost everywhere south of Valence. Our destination was different. Where we were going the seasonal movement of livestock does not mean variations in Easyjet's schedules, but transhumance: shepherding as practised by prehistoric nomads. It can be found within an hour of the Promenade des Anglais. It is called the Arriere-Pays Nicois.

You leave Nice by the N202 and, since where we are going has no shops, it was necessary to buy supplies. So into an enormous Carrefour at Lingostieres, the sort of place where you can find a semi-rigid inflatable dinghy, a caravan, depressing knickers and food. Amazing how the enduring myth of French style and culture survives exposure to the bruising realities of such artless, depressing, soviets of consumption. And the same might be said of the next town, St Martin du Var. Here, keeping my own damaged version of the myth of French style and culture intact, we looked optimistically for lunch, my memory telling me there was a good restaurant in the area and I was determined to have a final urban experience before joining the sheep and the eagles at altitude.

St Martin du Var is as unpromising for an unscheduled gastronomic adventure as Redditch. In the ambitiously named Restaurant du Bon Vin, a booze-bloomed barman with goatee and an English football shirt was serving sour yellow beer to skinheads. A three-legged dog hobbled around. A room at the back, separated from the bar by poorly laundered net curtains, had not yet taken inspiration from Cote Sud's strictures on Provencal decoration and, instead, exploited plastic laminate to the limits of its art. We looked at the menu of shredded carrot and horse and decided to move on.

The only other source of food in this town, suffering during our brief stay from a violent summer squall, was a traiteur selling depressing grey bread sandwiches filled with tinned champignons. We moved on again.

Twenty minutes later, the road suddenly begins to leave a wide river valley to explore more dramatic geology. The Defile du Chaudan is what 18th-century travellers sought in terms of thrilling horror, the hitherto confident road suddenly reduced to a thread between looming rock formations that are cadet, but ambitious, mountains. The sun has disappeared.

It is easy here to imagine Napoleonic armies on the march, their conquest of the intimidating natural features a morale-boosting exercise. Romantic paintings were inspired by such scenes and you quickly realise what a strange movement Romanticism was, taking its pleasure from intimate flirtations with calamity. And just as suddenly the road turns through a big sweep, you are out of the dark defile and into another valley, but bright and green and lush this time, not white and rocky as it was leaving Nice.

This is the road that leads to Digne, following the river and a mountain railway, but we get off at Entrevaux, a picture-perfect little town that was fortified by the great engineer Marechal Vauban. I know from past visits that this is my last chance of a draught beer, so we find ourselves in a favourite cafe contemplating Entrevaux's citadel, precariously sited atop a jagged canine tooth of a rock. It is always surprising there is never a pleading maiden waving a hanky from one of its vertiginous windows.

A wedding is in town and the band is incongruously playing the jaunty US Marine Corps song 'From the halls of Montezuma/To the shores of Tripoli' and I find myself humming along as a corrective to mounting anxiety about the terrifying road I know we soon have to drive along to reach the house. Despite the sunshine, there is an atmosphere of gloom. Like all towns that attract mountaineers, there are people trudging aimlessly, giving off apprehension. Our ultimate destination is just five or six kilometres of mountaineering down a D road, a hamlet discovered by a robust New Zealander friend of ours.

He is a sort of modern uomo universale. An award-winning photographer, perpetually on the road and in the air, he lives in London and Florence, can shear a sheep, cook paella for 200 using a garden rake as an implement, service a Land Rover and build a house with his own hands. This he has done. To our friend, occasional rockfalls and continuous vertigo experienced en route to his hamlet are small prices - indeed, romantic diversions - to pay for the profound senses of tranquillity and isolation enjoyed on arrival.

For the next few weeks this extraordinary strip of road is both a symbol and definition of my escape: its aggressive cambers, blind corners, sheer drops, irrational gradients, insane hairpins, almost unendurable vistas of altitudinous horror are lived through daily as if a spatial diagram of toiling anxiety and, eventually, well-earned repose. It is essentially a ledge cut into the side of a mountain. It actually looks like a case study by France's Ecole des Ponts et Chaussees, the world's oldest and boldest civil engineering school. But it does not look like a finished project, just a preliminary and alarmingly unfinished sketch. Leaving Entrevaux, the road is steep, but not too threatening, winding through scattered bourgeois villas. Then suddenly, the perceptual psychology becomes very demanding indeed: through a smaller defile than the one experienced earlier, you turn a corner and the ledge appears to give out on to a vision that might have inspired Gustave Dore's illustrations to Dante's Inferno. The ledge appears to be luring us into space with oblivion beyond and nothing to save us from that irresistible but terrifying lust of falling. As a committed vertigo sufferer, the vista sets off all my autonomic panic responses. Fortunately my wife is driving so I can scream. We have done this road a hundred times and I have still not decided whether I feel more comfortable with my eyes closed or looking at the floor. So I often do both.

Amazing how long five or six kilometres can seem at crawling speed when violent death is a continuing option just a metre away from my left elbow. I have learnt every twist and turn of this road through the Val du Chalvagne. And I remind myself what Gustave Eiffel told his people when refusing to pay them more for working at height, that it was as bad to fall from 30m as 300, so: no deal. And then after one final hairpin we are at Le Champ, 650m above sea level. It is called The Field because in a landscape of gorges it is the only flat spot, a gentle pasture in violent scenery. There are sheep.

But Le Champ has no shop, no bar. The road defines it and here is where my experiment begins with the metaphysics of tedium, the psychology of isolation, the deep and soothing pleasure of doing nothing. The house is raw concrete and masonry, emotionally very comfortable, but scarcely luxurious, not at all designed.

There are three books: Fergus Henderson's Nose to Tail Eating, a first edition of Beauvilliers' classic cook book L'Art du Cuisinier and a curio about the migrations of caribou and the husbandry of the Esquimaugh. So you have to be economical with your literature. In circumstances such as these, Vanity Fair can survive three rereadings. You panic about running out of books, but the monotony is perfect. Every day has the same sound effects: the tinkling of sheep's bells, the distant tapping of an adze, an explosion of shattering noises when scattered neighbours use the (nostalgically urban) bottlebank. The shepherd comes and goes. You can set your own watch by him, but I note he does not wear one. There are no jets and we are beyond the reach of reliable mobile telephony.

I am deterred by that road, even as my normally harassed circadian rhythms deteriorate into general calm. So one day I selfishly and cravenly let my wife drive down to Entrevaux station to pick up our son, returning from Nice. In absolute silence I read the first paragraph of Beauvilliers: 'La cuisine, simple dans son origine, raffinee de siecle a siecle, est devenue un art difficile.' You could say, I muse, the same about urban life. And then I settle down to an exquisite solitary hour of plucking basil leaves and pounding them in a mortar to make pistou, my sole accompaniment the sound of the sheep's bells as the valley turns from orange-yellow-green to slate-blue-black. And then there was the pleasing sight of the car's returning headlamps. I never thought I could do pastoral.

In the city, a hundred things fill the day and still you feel restless and dissatisfied. In Le Champ I spent an hour just reading and enjoying and writing down the poetic list of towns on the circuit of the brocanteurs: Sisteron, Allos, Meolans, Colmars, Les Mees, Ongles, Pierrevert, Valensole, Sausses, Prads. And then we came back to London. The builders who had promised to have our new bathroom finished were nowhere to be found, but left plenty of debris as an earnest of good intentions. Without a bath in London we were promptly translated into anxious, spittle-flecked feral creatures. In the Arriere-Pays Nicois we enjoyed the aristocracy of utter timelessness.

So there you have the predicament of urban man. To use an unattributed quote from Cyril Connolly's Unquiet Grave: 'The anxiety of cities, the boredom of the countryside! Each time I return to London I contribute to a crime.' Despite the horrible road, I long to go back.

Essentials

Stephen Bayley and family travelled from London Waterloo to Avignon with Eurostar (08705 186186; www.eurostar.com). In July and August, Eurostar runs a direct service to Avignon, the rest of the year you need to change in Lille for a connecting service. Standard return fares from London to Avignon via Lille start from £109pp.